EBMUD s Renewable Energy Initiatives

Transcription

1 EBMUD s Renewable Energy Initiatives David R. Williams Director of Wastewater Presentation to: Metropolitan Water Reclamation District of Greater Chicago September 30, 2011

2 Topics Historical overview of the role of WW utilities A new role and the driving forces Introduction to EBMUD Renewable energy efforts Renewable energy credits and greenhouse gas offsets Looking forward POTW as a green factory

3 Historical Roles for Wastewater Utilities Protector of public health Protector of the environment

4 Historical Evolution of Concerns and Wastewater Treatment Objectives Period Pre-1970 Major Concern Waterborne disease and protection of human health Wastewater Treatment Objectives Eliminate pathogens with treatment and disinfection Degradation of aquatic environment with impacts to wildlife Reduce pollutant loading to receiving water bodies 2005 onward 1) Resource scarcity and costs 2) Climate change 1) Resource recovery from waste materials 2) Reduce carbon emissions

5 A New Role Emerges: Waste to Energy Biodiesel Biogas

6 Driving Forces Commodities pricing escalating rapidly with developing nations growing demand Climate change pressure to use fewer fossil fuels

7 East Bay Municipal Utility District Regional water and wastewater public agency serving the east San Francisco Bay Drinking water system serves 1.3 million people Wastewater system serves 650,000 people

8 Hydroelectric Power Two Hydropower Plants Pardee 30 MW Camanche 10 MW Production ~ 185,000MWh/yr Offsets ~ 70,000MT/yr CO 2

9 Existing On-site Generation Three 2.2-MW IC engines Avg. output is about 3.0 MW Historically met ~40% of plant load

10 New Renewable Energy Efforts

11 Photovoltaic Solar Facilities Sobrante ~ 600,000 kwh/yr Adeline ~ 40,000 kwh/yr PV Power Purchase Agreements 5 locations Total of ~1,290,000kWh/yr

12 Microturbines On-site cogeneration for office buildings

13 Resource Recovery (R2) Program

14 Unique Conditions at EBMUD Excess digester capacity available Plant site on network of major interstate highways Economies of scale Limited alternatives in major urban area In-house expertise to perform research

15 Waste Examples Started with: Septage Progressed to: Fats, oils, and greases (FOG) Expanded program includes: Food processing waste Winery waste Industrial/commercial process waste Well purge water Tank rinsate Animal processing waste Chicken blood Beef blood Turkey lungs Municipal and agricultural lagoon wastes

16 R2 Program Provides Robust treatment Renewable energy production Tip fee generation which helps keep rates low In the future Program may also provide Renewable Energy Credits and Greenhouse Gas (GHG) Credits

17 Low Strength Waste (Headworks)

18 Acceptance of Liquid Wastes Low Strength Waste Deliveries ~350,000 gpd

19 FOG / Biodiesel

20 Trap Grease to Biodiesel Pilot

21 FOG Experience FOG can cause blockages and SSOs EBMUD began accepting FOG ~10 years ago, in support of a regional control program Process and operations problems encountered during early years: 3-foot scum blanket build up in primary digesters Blinding-up on-line instrumentation Impacts on whole effluent toxicity testing Partnership with third party to harvest brown grease led to a pilot to convert brown grease to biodiesel Currently, EBMUD accepts FOG directly to our upgraded thermophilic well-mixed digesters

22 Trap Grease to Biodiesel Pilot Constructed a 100-gallon batch facility Produced 1,300 gallons of biodiesel

23 Biodiesel Pilot Results QUALITY: Biodiesel from brown grease can meet all ASTM quality requirements with the exception of ultra low sulfur VEHICLE COMPATIBILITY: No short term vehicle maintenance or performance issues SIMILAR TO COMMERCIAL: Feasible to use brown grease biodiesel or commercial biodiesel TRUST: Our drivers and mechanics gained some confidence in the fuel VALUABLE BYPRODUCT: Glycerin may be digested to produce more biogas

24 Full Scale Biodiesel Production costs could be competitive with petroleum diesel, if significant amount of interceptor grease is available Cost strongly influenced by economies of scale and method to identify and procure interceptor grease from wide area (and perhaps supplemental virgin oil) Technical hurdles remain including: Need for reliable cost effective means to convert interceptor waste (mostly water, some solids, about 2% grease ) to brown grease (a feedstock for biodiesel) Need for reliable cost effective means to reduce sulfur content to meet new California standards for Ultra Low Sulfur Diesel (15ppm)

25 EBMUD Future for Biodiesel Received $1M Grant from California Energy Commission to further research Cost-effective brown grease production Sulfur removal Securing land lease for glycerin waste Glycerin COD > 10x municipal sludge (700,000 ~ 1,000,000 mg/l) Negligible solids for disposal

26 FOG Receiving and Digester Blending Blend Tank 2 Blend Tank 1 FOG Tanks (Future in construction)

27 Food Waste

28 Food Waste Second largest category of municipal solid waste to landfills Less than 3% currently diverted, mainly for composting Diversion from landfill conserves space and reduces GHG emissions Organic material, like food waste, breaks down in a landfill and releases methane gas, which is a potent GHG

29 Food Waste Background Food waste is the largest single category of municipal solid waste in CA (16%) or 5.6 million tons (CIWMB, 1999) Key component for meeting mandated solid waste diversion goals (state law, AB 939) Composting is the most common diversion method Composting limitations: Net energy consumer, long process (90 days) Air quality concerns (VOCs) Anaerobic digestion has been successfully used to treat municipal sludge, but has not been widely used in the US for food waste.

30 Focus on Food Waste Food Waste creates 3.5 times the amount of energy as the same volume of municipal sludge Local sustainable feedstock for excess digester capacity Local solution to a local disposal problem benefiting the ratepayer and community 1 truck/day will power 260 homes (~0.2MW)

31 Food Waste Source Food waste comes from Bay Area communities and commercial facilities

32 Contaminants in Commercial Food Waste

33 Off-site Removal of Large Contaminants Local waste management company hauls and preprocesses food waste before it is anaerobically digested at EBMUD

34 Solid Liquid Waste Receiving Station

35 Food Waste Delivery at MWWTP

36 Food Waste Delivery

37 Contaminants in Delivered Clean Food Waste

38 Food Waste Contaminants Food waste contaminants led to processing problems - plugging, equipment damage. Contaminants included: Silverware, chopsticks, shells, bottle caps, plastics. EBMUD staff investigated processes to remove contaminants.

39 Patented Food Waste Process

40 Food Waste Processing EBMUD s Food Waste Processing System Processing Residuals for Compost

41 Food Waste Challenges Non-traditional; no existing model (in US) for food waste processing and digestion at a wastewater treatment plant Significant effort in innovation and development of technology and process Creation of new relationships with food waste providers (solid waste haulers, solid waste authorities) Food Waste processing challenges Understanding contaminant impacts to other treatment processes and equipment Developing cost-effective contaminant control options; at source (restaurants), with preprocessing, and/or post-digestion?

42 R2 Program Results

43 PGS Renewable Energy Expansion Project Installing a new 4.5 megawatt (MW) turbine to expand the existing Power Generation Station (online by July 2011) Current Three 2.1 MW Engines Future Add 4.5 MW Turbine + = 11 Become a net energy producer and reduce greenhouse gas emissions MW

44 Biogas Turbine

45 Renewable Energy Production Projected Full utilization of new 4.5MW turbine * Projected ** Assuming second 4.5 MW turbine * Slight drop in 2007 due to digester upgrade and engine overhaul projects **Out year projection assumes availability of acceptable waste streams

46 Current R2 Rates Material Type Rate ($/gal) Septage $0.07 FOG $0.11 (non-conc) / $0.15 (conc) Groundwater $0.02 Process Water $0.04 Gray Water $0.03 (<75k mg/l TDS) $0.06 (75k to 200k mg/l TDS) Sludge $0.05 (up to 3% TS) + $0.01 per % TS up to 20% Liquid Organic Material $0.03 Solid Organic Material $30 to $65/ton

47 Tip Fee and Energy Revenue

48 Trucked Waste Acceptance Challenges Rigorous acceptance criteria to ensure process integrity On-going research and pilot digester studies for evaluation Impacts to other treatment processes and equipment from sidestreams New system developed for tracking deliveries and invoicing

49 R2 Program Lessons Learned Anaerobic Digestion Robust way to convert a range of organics to methane gas/energy Good mix of waste streams needed to maintain digester health Demonstrated operation outside published parameters with careful monitoring Regulatory Framework May be entering solid waste permitting arena Exploring merits of a rendering license Think Like a Business Balancing traditional O&M perspectives with market-based considerations 24-7 deliveries Can you afford plant shutdowns and turning away trucks that depend on you? Staff buy-in for cost-benefit of plant impacts with revenue and energy production? Revenue stream is not locked down to one site; e.g., FOG volumes and tipping fees can plummet as more POTWs begin to accept this material Public Perception High level of interest Understand need to look for opportunities for renewable fuels/energy Managing related odors is a key to long-term success

50 New Revenue Opportunities Renewable Energy Credits and Offsets

51 Renewable Energy Credits (REC) A REC is the environmental attribute associated with the renewable energy Aka green tag Typically sold in units of MWh Unbundled from the electricity it could be sold separately

52 Renewable Portfolio Standard California s RPS is 20% by 2010 for investor-owned utilities (IOUs) IOUs might meet the RPS by purchasing RECs 20% by 2010!

53 Expected Evolution of REC Sales in California PAST No REC PRESENT Bundled REC FUTURE? Unbundled REC REC to Buyer 2 Electricity only to buyer Electricity and REC to buyer Electricity to Buyer 1

54 Greenhouse Gas Markets AB 32 requires GHG emission reductions to 1990 baseline levels by 2020 (~25%) California Air Resources Board (CARB) recommends cap and trade approach to reducing emissions Greenhouse gas (GHG) offsets are a potential component of cap and trade system

55 Emissions Trading: Allowances vs. Offsets $ CO2e Reductions

56 Revenue Opportunities? For WWTPs with renewable generation: Green premium for power or REC sale Possible GHG offset revenue for waste diversions, e.g., food wastes diverted from landfills

57 Looking to the Future

58 Food Waste Sourcing Interest in securing long term commitments with local food waste providers Signed a contract with Central Contra Costa Solid Waste Authority 5.5-year contract for up to 15 tons per day (tpd) Tip fee starting at $45/ton and escalating annually Sharing of any REC or GHG credits TBD Signed contract with Recology 10 to 20 year contract for 120 tpd Tip fee starting at ~$46 and escalating annually Sharing of energy value and REC Land-lease to Recology for construction of a Food Waste Receiving and Preprocessing Facility

59 New R2 Wastes Competition for organic waste from other POTWs continues to grow so focus for growth is on wastes that are more complicated from a technical or regulatory perspective, e.g.: Residential Food Waste Green Waste Biofuel By-products Field Dead and other Animal Processing Byproducts

60 THE WWTP AS A GREEN FACTORY

61 A New Role for WWTPs? Historically: A protector New Role: A provider Forces driving new role: Natural resource scarcity Climate change Producing green products can help to reduce WWTP s carbon footprint

62 Possible Green Products other high strength organic waste electricity biofuel food waste fertilizer wastewater water for industry & irrigation

63 Challenges and Opportunities Challenges Opportunities Waste to Energy R&D investments Impacts to existing treatment processes Capital req ts for new facilities Greater energy self-sufficiency and associated cost savings New revenue streams from environmental commodities Reduced carbon footprint Mgmt of energy purchases and sales GHG emissions compliance Potential to pass on savings to ratepayers Value of offsets and REC s from renewable energy

64 Closing the Materials Cycle Loop Manufacturing Distribution Consumption Natural Resources Disposal Waste Recycling

65 ? Questions